1. Field of the Invention
The present invention relates to a composite metal sheet, a method for joining metal sheets, and a device for joining metal sheets. In particular, the present invention relates to a composite metal sheet formed by joining two metal sheets, a method for joining two metal sheets, and a device for joining two metal sheets.
2. Description of the Related Art
Conventionally, for joining metal sheets together swaging these metal sheets together has already been known in the art. However, such a swaging technology has a defect that satisfactory electrical property cannot be achieved. This is because such a technology only depends on remaining stress and contact force occurring in response to swaging treatment. Also, there is a plurality of gaps in the area of contact, which generally causes corrosion in the corresponding area. As a result, long term-electrical property is hardly kept.
Furthermore, to achieve such a long-term electrical property, it is proposed to join metal sheets together by soldering via plasma. Meanwhile, such a method has a defect that process automation is difficult to set up, and therefore is not suited for large-scale manufacture. Accordingly, it is not cost-effective job.
To solve the afore-mentioned problems, the present inventors have studied a composite metal sheet having remarkably enhanced electrical property and reliability, a cost-effective method for preparation the same, and a cost-effective device for producing the same.